We have implemented a service stack service that calls a ORMLite database. We are using self hosted services.
The database has a single open connection. A bug in another program highlighted a problem. If the webserice gets called twice very quickly we get this error thrown.
Stack=MySql.Data.MySqlClient.MySqlException (0x80004005): There is already an open DataReader associated with this Connection which must be closed first.
at MySql.Data.MySqlClient.ExceptionInterceptor.Throw(Exception exception)
at MySql.Data.MySqlClient.MySqlConnection.Throw(Exception ex)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader()
at ServiceStack.OrmLite.OrmLiteCommand.ExecuteReader()
at ServiceStack.OrmLite.OrmLiteReadCommandExtensions.ExecReader(IDbCommand dbCmd, String sql)
at ServiceStack.OrmLite.OrmLiteResultsFilterExtensions.ExprConvertToList[T](IDbCommand dbCmd, String sql, IEnumerable1 sqlParams, HashSet1 onlyFields)
at ServiceStack.OrmLite.Support.LoadList2..ctor(IDbCommand dbCmd, SqlExpression1 q)
at ServiceStack.OrmLite.OrmLiteReadCommandExtensions.LoadListWithReferences[Into,From](IDbCommand dbCmd, SqlExpression1 expr, IEnumerable1 include)
at ServiceStack.OrmLite.ReadExpressionCommandExtensions.LoadSelect[T](IDbCommand dbCmd, Expression1 predicate, IEnumerable1 include)
at ServiceStack.OrmLite.OrmLiteReadExpressionsApi.<>c__DisplayClass34_01.<LoadSelect>b__0(IDbCommand dbCmd) at ServiceStack.OrmLite.OrmLiteExecFilter.Exec[T](IDbConnection dbConn, Func2 filter)
at ServiceStack.OrmLite.OrmLiteReadExpressionsApi.Exec[T](IDbConnection dbConn, Func2 filter) at ServiceStack.OrmLite.OrmLiteReadExpressionsApi.LoadSelect[T](IDbConnection dbConn, Expression1 predicate, String[] include)
Q1: is there any simple way to fix this?
Q2: The problem can be fixed by, wrapping every call with a lock or calling DbOrmConnectionFactory.Open() before every ORM request. Both will have a performance cost.
In WCF I remember you could tell the service to only allow X instances of its self to be created.
Then you put the SQlconnection in the session, which would be remain open between calls. This is just an idea.
Is is possible?